Typically, an antenna device is known in which electrical power to a radiating element, which is formed on a circuit board, is fed using a coaxial line or a coaxial connector having a coaxial structure and installed on the outside of the circuit board. In such an antenna device, electrical power to a radiating element is fed by establishing electrical continuity between an inner electrical conductor of the coaxial line and the signal line of a stripline.
Regarding a method for establishing electrical continuity between the coaxial line and the stripline; a method is known in which, for example, electrical continuity between the inner electrical conductor of the coaxial line and the signal line of the stripline is established using a non-through via hole formed on the circuit board. There is another method in which electrical continuity between the inner electrical conductor of the coaxial line and the signal line of the stripline is established using a through hole formed in a penetrating manner on the circuit board.
However, in the conventional via-hole-based method of establishing electrical continuity; since a non-through via hole is formed, it results in an increase in the manufacturing cost. Moreover, in the conventional through-hole-based method of establishing electrical continuity, it is necessary to keep a gap between the through hole and a grounded conductor. For that reason, in the through-hole-based method of establishing electrical continuity, the communication quality of the antenna device decreases in consequence of the leakage of radio waves through the gap.